Coherent light generators – Particular temperature control – Heat sink
Reexamination Certificate
2000-11-16
2004-08-17
Porta, David (Department: 2878)
Coherent light generators
Particular temperature control
Heat sink
C372S034000
Reexamination Certificate
active
06778568
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a semiconductor module and a method of mounting a semiconductor laser element on the semiconductor module.
2. Description of the Related Art
As is well known, an optical pickup for reading information recorded on an optical disks, such as a CD and DVD, can optically read the information such that a laser beam emitted from a semiconductor laser element, which serves as a light source, disposed in a main body, is guided to an objective lens along an optical path of a predetermined optical system made up of various optical components. A light beam gathered by the objective lens is then projected onto the information recording surface of the optical disk, reflected light that has undergone light modulation according to the recorded information of the optical disk is then generated. The reflected light is then guided again through the objective lens to a light receiving element along a predetermined optical path, and, based on the output of received light, the light receiving element generates a signal according to the recorded information of the optical disk.
In an optical pickup such as this, in order to read recorded information of the optical disk accurately, it is required that a laser beam of a predetermined wavelength emitted from the semiconductor laser element be caused to, without being out of alignment with an optical axis, fall upon the predetermined optical system and generate a light beam by the light gathering of the objective lens, and the light beam be focused at an appropriate position on the information recording surface of the optical disk. To do so, the semiconductor laser element must be disposed so to have no axial deviation with respect to the optical system and take an appropriate position in the axial direction of the laser beam with respect to the predetermined optical system.
If the semiconductor laser element is not disposed properly with respect to the optical system, the laser beam is made incident in a deviated state of the optical axis of the laser beam with respect to the optical axis of the optical system. Accordingly, the incident position of the light beam on the information recording surface or the incident angle of the light beam deviates from an allowable range, so that reflected light does not undergo accurate light modulation by recorded information, and the incident position of the obtained reflected light on the light receiving element deviates greatly. As a result, it is impossible not only to obtain a sufficient amount of reflected light but also to allow the reflected light to undergo accurate light modulation according to recorded information. This often makes it impossible to accurately read the recorded information by means of the reflected light.
Therefore, in the optical pickup, some optical components, which are to be disposed beforehand at predetermined positions in the main body, are each fixed at a predetermined position in the main body properly, and the semiconductor laser element is mounted in the body so as to be positionally adjustable with respect to the optical system made up of the optical components, and, thereafter, the optical position of the semiconductor laser element is adjusted with respect to the optical system.
The semiconductor laser element is inserted into a holding hole formed in, for example, a heat radiation member made of a material that has heat radiating properties as if the laser element is dropped thereinto, and the heat radiation member is mounted in a main body in a state in which the laser element is held in the heat radiation member while being pressed by, for example, a leaf spring. By moving the semiconductor laser element with respect to the pressing leaf spring, positional adjustment can be made in a planar direction (x-y axis direction) perpendicular to an axial direction (z axis direction) of the laser beam emitted from the semiconductor laser element.
The heat radiation member for holding the semiconductor laser element is held in the main body, and is mounted to be movable and adjustable in the direction of the optical axis (z axis direction) of the laser beam emitted from the semiconductor laser element with respect to a case. The positional adjustment in the directions of the three axes (x axis, y axis and z axis) is repeatedly carried out for each axial direction by the use of an adjusting fixture, and, thereby, the positional adjustment of the semiconductor laser element with respect to the heat radiation member and the positional adjustment of the heat radiation member with respect to the case are carried out, and, as a result, the adjustment of the optical position of the semiconductor laser element is carried out.
In order to adjust the optical position of the semiconductor laser element of the conventional optical pickup, in addition to the adjusting method carried out by arranging the optical components as mentioned above, there is another adjusting method in which, for example, the semiconductor laser element is mounted to be movable and adjustable in the directions of two axes (x axis and y axis) with respect to the pickup body, and the light receiving element (PD) among the other optical systems is mounted to be movable and adjustable in the axial direction (z axis direction) of the laser beam. In this method, the positional adjustment of the laser beam in the directions of the three axes (x axis, y axis, and z axis) is carried out by repeatedly carrying out the axial adjustment (x-y adjustment) of the semiconductor laser element and the axial adjustment (z adjustment) of the light receiving element (PD).
As mentioned above, the adjustment of the optical position of the laser beam of the semiconductor laser element must be repeatedly carried out in the direction of each axis after the semiconductor laser element, the light receiving element, etc., are temporarily mounted in the case. Therefore, much time is consumed to complete the adjustment of the optical position thereof.
OBJECTS AND SUMMARY OF THE INVENTION
The present invention was made in consideration of the above problem, and it is an object of the present invention to provide a semiconductor module capable of mounting a semiconductor laser element promptly and reliably at a predetermined optical position with respect to an optical system formed in the case of a semiconductor module and provide a mounting method of the semiconductor laser element of the semiconductor module.
According to a first aspect of the present invention, a semiconductor module comprises a semiconductor laser element; a holding member for fixedly holding the semiconductor laser element, the holding member having thermal conductivity; a base member for fixedly holding the holding member, the base member having thermal conductivity; and a case for fixedly holding the base member; in which a laser beam emitted from the semiconductor laser element is guided to a predetermined optical system disposed in the case and is projected out of the semiconductor module, and by fixing the holding member that fixedly holds the semiconductor laser element to the base member by means of a thermal type adhesive member that has thermal conductivity, the semiconductor laser element is fixed at a predetermined optical position where optical adjustment with respect to the optical system has been carried out.
In the semiconductor module according to the first aspect of the present invention, the semiconductor laser element can be promptly and reliably mounted at the predetermined optical position where optical adjustment with respect to the optical system of the case has been carried out, and, after mounting the semiconductor laser element, there is no need to adjust the optical position of the laser beam of the semiconductor laser element.
Further, in the semiconductor module according to the first aspect of the present invention, since the semiconductor laser element, the holding member, the adhesive member, and the base member make up a thermal path that has thermal conductivity, the he
Fukuda Shinnosuke
Ishida Takeshi
Okayasu Masaki
Shimomura Kiyoshi
Tanaka Hirofumi
Monbleau Davienne
Perman & Green LLP
Pioneer Corporation
Porta David
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